The invention comprises an effective, efficient, and economical system for in-situ sampling, testing, detection and/or for preparation for remediation of soil, bedrock, and ground water contamination. The system provides for the collection of soil vapor, for the collection of soil and bedrock samples from discrete intervals and for the collection of ground water samples. The system facilitates the construction of temporary or permanent ground water monitoring wells for collecting ground water samples and in-situ air permeability testing. The system affords multiple site characterization techniques for investigating and remediating contaminated soils and ground water.
At locations where soil, bedrock, and/or ground water contamination occurs, it is often desirable to collect soil vapor data from the site to determine the extent of vapor phase contamination. A monitoring system to sample soil vapor would have enhanced effectiveness, efficiency, and economy if the same apparatus could be used to collect soil samples, ground water samples and to complete ground water monitoring wells, as desired or required. It would also be desirable to have the above apparatus capable of installing and testing remediation equipment. The system would have even further general application if the drilling mechanism were capable of boring through bedrock and consolidated formations as well as through alluvial materials and unconsolidated formations. Prior to this invention, drilling systems have not been offered to provide this effective and efficient combination of field data collection and well completion techniques through soil and bedrock.
Prior and present art soil vapor surveying techniques use hand drilling and hydraulic drilling. The industry has stayed away from pneumatic drilling because of a general belief that pneumatic drilling would distort the soil vapor data. The present inventors, faced with the daunting task of environmental surveying through bedrock, experimented nonetheless with pneumatic drilling, notwithstanding the negative reception it receives in the art. The inventors learned that, unexpectedly, an air balance is apparently achieved downhole. Air pressure and venturi effects may cancel each other out at the probe tip. Pneumatic drilling can be used for environmental sampling and it does not impermissibly dilute or destroy the soil vapors sampled or the significance of the vapor analysis data.
In contrast to prior art soil vapor sampling machines and techniques, the present invention, through the use of pneumatic drilling equipment, is not only able to sample through bedrock but also is able to efficiently and effectively provide a technique capable of water sampling as well as soil sampling and capable of the installation of ground water monitoring wells in both alluvial materials and bedrock formations. The subject invention provides the synergistic advantage of performing multiple field investigative tasks both in alluvial and bedrock subsurface environments. By performing soil vapor surveys, collecting soil and/or ground water samples for laboratory analysis, and installing ground water monitoring wells and remediation equipment in both bedrock and alluvial materials, the system qualifies uniquely to offer a range of field services not currently found in the trade.
Some specific advantages of the system's drilling apparatus and technique are that it uses conventional rock bits which allow a rapid drilling rate in both alluvial and bedrock environments. Consequently, site characterization and the remediation of contaminated sites can be achieved at a rapid pace, allowing the system to provide more information to land owners for a lesser cost than the alternative of using a combination of prior systems. Furthermore, the drill cuttings (contaminated wastes) produced by the drilling apparatus and technique are of substantially less volume than that produced by many other drilling techniques, thereby reducing contaminated soil disposal costs. Because of the drilling procedure utilized, the apparatus provides a cleaner borehole wall than that offered by other drilling techniques. A cleaner borehole wall allows any remediation system installed to become effective more quickly. The apparatus and system of the present invention is further unique in the trade in that in addition to investigative techniques, it can be utilized to both install and test air sparging/vacuum extraction remediation systems. Once the remediation equipment is installed (sparge or vacuum point), the machine may be used to inject air into the sparge pipes and measure air pressure responses in the borehole located at varying distances from the air injection point. This data can then be used to determine the effective air permeability of soils/bedrock for the efficient design of remediation systems which use air sparging/vacuum extraction independently or together. As cost control is becoming an increasingly important issue for environmental investigation and remediation, an apparatus and system that performs more efficiently and effectively both investigative and remediation tasks through a variety of subsurface environments is of enhanced value.